This invention relates to an automatic sampling arrangement for supplying liquid samples to an analytical instrument such as an atomic absorption spectrophotometer. An atomic absorption spectrophotometer having automatic microprocessor controlled means for carrying out a succession of analyses is described in U.K Patent Application Nos. 8133968 (PHB 32832); 8201371 (PHB 32848); 8201372 (PHB 32849) and 8201373 (PHB 32850) and is manufactured and sold by Pye Unicam Limited under the type number PU9000. It is desirable for the samples to be made available to such an instrument under the control of the microprocessor.
An automatic sampling arrangement is known from published European Patent Application No. 0,015,025 (PP 1234) for supplying liquid samples to an analytical instrument, in this case a flameless atomic absorption spectrophotometer. This sampling arrangement comprises a compartment within which a sample carrier in the form of a turntable may be located, the turntable having a plurality of locations for sample containers arranged on a circle centered on the axis of rotation of the turntable, and a sampling mechanism for aspirating a sample from a sample container when the turntable is indexed to bring one of the sample locations in registration therewith. In this known sampling arrangement the turntable has only one circular rank of sample locations and also the details of the analytical function to be performed on each sample are encoded on the turntable by mechanical means comprising corresponding circular ranks of holes which are either left open or blocked to form a code corresponding to the function. The turntable is mounted on a central spindle.